To date, few combinations of antiretrovirals have been studied in large cohorts of stable HIV-1 infected, antiretroviral experienced children. As the duration of the efficacy of continuing stable therapy is undefined and the indications for timing of changes in therapy for children are not clear, it is important that new therapeutic regimens are identified and their durability characterized. Accumulating evidence supports combination therapy with two or more antiviral agents as beneficial in the long-term management of HIV infection. It is hypothesized that the development of HIV-1 resistance to individual agents will be delayed by maintaining undetectable or very low levels of viral replication. Pram 2 will be used to determine the level of antiviral activity of the following four treatment arms. Arm A: d4T/Nevirapine/Ritonavir Arm B: d4T/3TC/Nelfinavir Arm C: d4T/Nevirapine/Nelfinavir Arm D: d4T/3TC/Nevirapine/Nelfinavir